Effects of maternal over- and undernutrition on intestinal morphology, enzyme activity, and gene expression of nutrient transporters in newborn and weaned pigs

The importance of optimal body condition to maximise reproductive health and perinatal outcomes in pigs

Overnutrition or undernutrition during all or part of the reproductive cycle predisposes sows to metabolic consequences and poor reproductive health which contributes to a decrease in sow longevity and an increase in perinatal mortality. This represents not only an economic problem for the pig industry but also results in poor animal welfare. To maximise profitability and increase sustainability in pig production, it is pivotal to provide researchers and practitioners with synthesised information about the repercussions of maternal obesity or malnutrition on reproductive health and perinatal outcomes, and to pinpoint currently available nutritional managements to keep sows' body condition in an optimal range. Thus, the present review summarises recent work on the consequences of maternal malnutrition and highlights new findings.

Polar lipid-enriched milk fat globule membrane supplementation in maternal high-fat diet promotes intestinal barrier function and modulates gut microbiota in male offspring

Intestinal development plays a critical role in physiology and disease in early life and has long-term effects on the health status throughout the lifespan. Maternal high-fat diet (HFD) fuels the inflammatory reaction and metabolic syndrome, disrupts intestinal barrier function, and alters gut microbiota in offspring. The aim of this study was to evaluate whether polar lipid-enriched milk fat globule membrane (MFGM-PL) supplementation in maternal HFD could promote intestinal barrier function and modulate gut microbiota in male offspring. Obese female rats induced by HFD were supplemented with MFGM-PL during pregnancy and lactation. The offspring were fed HFD for 11 weeks after weaning. MFGM-PL supplementation to dams fed HFD decreased the body weight gain and ameliorated abnormalities of serum insulin, lipids, and inflammatory cytokines in offspring at weaning. Maternal MFGM-PL supplementation promoted the intestinal barrier by increasing the expression of Ki-67, lysozyme, mucin 2, zonula occludens-1, claudin-3, and occludin. Additionally, MFGM-PL supplementation to HFD dams improved gut dysbiosis in offspring. MFGM-PL increased the relative abundance of Akkermansiaceae, Ruminococcaceae, and Blautia. Concomitantly, maternal MFGM-PL treatment increased short-chain fatty acids of colonic contents and G-protein-coupled receptor (GPR) 41 and GPR 43 expressions in the colon of offspring. Importantly, the beneficial effects of maternal MFGM-PL intervention persisted to offspring's adulthood, as evidenced by increased relative abundance of norank_f_Muribaculaceae, Peptostreptococcaceae and Romboutsia and modulated the taxonomic diversity of gut microbiota in adult offspring. In summary, maternal MFGM-PL supplementation improved intestinal development in the offspring of dams fed with HFD, which exerted long-term beneficial effects on offspring intestinal health.

Effect of yeast culture supplementation in sows during late gestation and lactation on growth performance, antioxidant properties, and intestinal microorganisms of offspring weaned piglets

Introduction

The effects of maternal addition of yeast cultures on offspring gut development and intestinal microorganisms are not yet known, so the aim of this study was to investigate the effects of maternal addition of yeast cultures to the diet of sows during late gestation and lactation on growth performance, antioxidant properties and intestinal microorganisms of offspring weaned piglets.

Methods

40 Landrace × Yorkshire sows (3-7 of parity) with similar backfat were randomly divided into two treatment groups: control diet (CON) and control diet +2.0 g/kg yeast culture (XPC), and the trial started on day 90 of gestation and ended on day 21 of lactation.

Results

The results showed that maternal addition of yeast culture significantly increased weaned piglet weight and mean daily gain (p < 0.05), with a tendency to increase litter weight gain (p = 0.083) and liver weight (p = 0.076) compared to the control group. The content of thymus malondialdehyde (MDA) was significantly higher (p < 0.05) and the content of colon total antioxidant capacity (T-AOC) was significantly lower (p < 0.05) in the offspring weaned piglets of the XPC group compared to the control group. The expression of thymus SOD1 and SOD2, spleen SOD1, jejunum SOD2, and colon GPX1, SOD1, and SOD2 were significantly downregulated in the XPC group of offspring weaned piglets compared with the control group (p < 0.05). The intestinal morphology and the content of short-chain fatty acids in colonic chyme did not differ between the two groups (p > 0.05). Compared with the control group, the XPC group significantly increased the relative abundance of colonic chyme Bacteroidetes (p < 0.05), tended to decrease the relative abundance of Lactobacillus (p = 0.078), and tended to increase the relative abundance of Alloprevotella (p = 0.055). The XPC group significantly upregulated Blautia and Fournierella (p < 0.05) and significantly downregulated Candidatus_Competibacter, Nitrospira, Dechloromonas, Haliangium, and Oscillospira (p < 0.05).

Discussion

In conclusion, maternal addition of yeast cultures improved the growth performance of offspring weaned piglets and changed the intestinal microbial community, but did not improve their antioxidant performance.

Yeast culture supplementation of sow diets regulates the immune performance of their weaned piglets under lipopolysaccharide stress

The aim of this study was to investigate the effect of dietary supplementation of sows with yeast cultures (XPC) during late gestation and lactation on the immune performance of their weaned offspring under lipopolysaccharide (LPS) stress. A total of 40 Landrace × Yorkshire sows (parity 3 to 7) with similar backfat thickness were selected and randomly divided into two treatment groups: a control group (basal diet) and a yeast culture group (basal diet + 2.0 g/kg XPC). The trial was conducted from day 90 of gestation to day 21 of lactation. At the end of the experiment, 12 piglets with similar weights were selected from each group and slaughtered 4 h after intraperitoneal injection with either saline or LPS. The results showed that the concentrations of interleukin-6 (IL-6) in the thymus and tumor necrosis factor-α in the liver increased significantly (P < 0.05) in weaned piglets after LPS injection. Maternal dietary supplementation with XPC significantly reduced the concentration of inflammatory factors in the plasma and thymus of weaned piglets (P < 0.05). LPS injection significantly upregulated the expression of some tissue inflammation-related genes, significantly downregulated the expression of intestinal tight junction-related genes, and significantly elevated the protein expression of liver phospho-nuclear factor kappa B (p-NF-κB), the phospho-inhibitory subunit of NF-κB (p-IκBα), phospho-c-Jun N-terminal kinase (p-JNK), Nuclear factor kappa-B (NF-κB), and the inhibitory subunit of NF-κB (IκBα) in weaned piglets (P < 0.05). Maternal dietary supplementation with XPC significantly downregulated the gene expression of IL-6 and interleukin-10 (IL-10) in the thymus and decreased the protein expression of c-Jun N-terminal kinase (JNK) in the liver of weaned piglets (P < 0.05). In summary, injection of LPS induced an inflammatory response in weaned piglets and destroyed the intestinal barrier. Maternal dietary supplementation of XPC improved the immune performance of weaned piglets by inhibiting inflammatory responses.

Prospect of potential intrauterine programming impacts associated with COVID-19

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) - 2019 (COVID-19) has led to a worldwide public health concern. In addition to immediate impacts on human health and well-being, COVID-19 can result in unfortunate and long-term health consequences for future generations. In particular, pregnant women and developing fetuses in low-income settings could be prone to a higher risk of undernutrition, often due to an inadequate supply of food and nutrition during a pandemic outbreak like COVID-19. Such situations can subsequently lead to an increased risk of undesirable health consequences, such as non-communicable diseases, including obesity, metabolic syndrome, hypertension, and type 2 diabetes, in individuals born to exposed mothers via fetal programming. Moreover, COVID-19 infection or related stress during pregnancy can induce long-term programming outcomes on neuroendocrinological systems in offspring after birth. However, the long-lasting consequences of the transplacental transmission of COVID-19 in offspring are currently unknown. Here we hypothesize that a COVID-19 pandemic triggers intrauterine programming outcomes in offspring due to multiple maternal factors (e.g., nutrition deficiency, stress, infection, inflammation) during pregnancy. Thus, it is crucial to establish an integrated lifetime health information system for individuals born in or around the COVID-19 pandemic to identify those at risk of adverse pre-and postnatal nutritional programming. This approach will assist in designing specific dietary or other nutritional interventions to minimize the potential undesirable outcomes in those nutritionally programmed individuals.

Long-term maternal intake of inulin exacerbated the intestinal damage and inflammation of offspring rats in a DSS-induced colitis model

This study aimed to investigate the effects of long-term maternal intake of inulin on intestinal morphology, permeability, inflammation and microbiota of offspring rats treated with dextran sulfate sodium (DSS). Sixteen female adult Sprague-Dawley rats were assigned to two groups receiving the fiber-free diet (FFD) or inulin diet (INU, 5% inulin) for three parities. The offspring weaned rats (third-parity) were fed with the same diet for four weeks until receiving 6% DSS for 7 days; the four groups were as follows: FFD, FFD + DSS, INU and INU + DSS. The results showed that maternal intake of inulin increased the histopathology score and activity of diamine oxidase (DAO) in serum, and the highest histopathology scores and activity of DAO were observed in INU + DSS rats. Maternal intake of inulin increased the activity of myeloperoxidase (MPO), mRNA expressions of inflammatory factors and protein expression of IL-1β in colonic tissues. Likewise, INU + DSS rats had the highest activity of MPO and mRNA expressions of inflammatory factors in colonic tissues. Maternal intake of inulin increased the abundances of Bacteroidetes, Bacteroides and Parasutterella, which were the highest enriched in INU + DSS rats. The level of acetate in the colonic digesta of INU + DSS rats was lower than that in FFD and INU rats. These results indicated that long-term maternal intake of inulin exacerbated the intestinal damage and inflammation of DSS-induced offspring rats, associated with the decreased level of acetate and altered intestinal microbiota.

Lycopene improves maternal reproductive performance by modulating milk composition and placental antioxidative and immune status

Placental health and milk quality are important for maternal reproductive performance during pregnancy and lactation. Lycopene plays an important role in antioxidation, anti-inflammation and regulating lipid metabolism. The goal of the present study was to investigate the effects of dietary lycopene supplementation in the pig model on reproductive performance, placental health and milk composition during maternal gestation and lactation. In the present study, the litter size of live piglets was increased and the litter size of dead piglets was decreased by lycopene supplementation of the diet of sows. The litter weight at birth and weaning were increased in the lycopene group. Through placental proteomics, we enriched differentially expressed proteins (DEPs), gene ontology (GO) terms, and Kyoto encyclopedia of proteins and genomes (KEGG) pathways involved in immunity, anti-inflammation, antioxidants, and lipid metabolism and transport. Furthermore, in terms of placental health, we analyzed the levels of related enzymes, metabolites and mRNA expression in the placenta. Lycopene was shown to reduce mRNA expression and the levels of placental inflammatory factors, increase the content of immunoglobulin, improve the antioxidant capacity, and improve lipid metabolism and lipid transport in the placenta. In terms of sow milk composition, lycopene increased the levels of immunoglobulins in colostrum and lactose in colostrum and milk. Overall, the results of the present study demonstrate that dietary lycopene supplementation of sows during gestation and lactation improves the reproductive performance to a certain extent; this may be due to lycopene improving the placental health and milk composition of sows.

Precision feeding gestating sows: effects on offspring growth performance and carcass and loin quality at slaughter

A total of 601 pigs from 65 litters were used to determine the effects of closely meeting estimated daily Lys and energy requirements for sows during gestation for three consecutive parities on offspring postweaning growth performance and carcass and loin quality at slaughter. Sows were assigned a control (static diet composition; CON) or precision (individual daily blend of two diets to meet estimated Lys and energy requirements; PRE) feeding program between days 7 and 110 of gestation for three consecutive pregnancy cycles, starting with primiparous sows (parity 1: 12 CON and 12 PRE sows; parity 2: 8 CON and 13 PRE sows; parity 3: 8 CON and 12 PRE sows). At weaning (20 ± 2 d of age), up to 10 pigs per litter were randomly selected and placed in a pen (1 litter per pen). All pens received ad libitum access to commercial diets in six phases (four-phase nursery, grower, and finisher, respectively). Four pigs per pen were slaughtered at ~125 kg BW for evaluation of carcass characteristics and loin quality. The ADG and ADFI of offspring were not influenced by maternal feeding program in any parity during nursery phases I through III. During nursery phase IV, ADG and ADFI were greater for litters from PRE- vs. CON-fed sows (0.70 vs. 0.66 ± 0.03 and 1.15 vs. 1.08 ± 0.06 kg/d for ADG and ADFI, respectively; P < 0.05). The BW for litters from PRE- vs. CON-fed sows tended to be greater by day 66 of age (end of nursery period; 29.7 vs. 28.7 ± 1.1 kg; P = 0.076). Within the grower phase, litters from PRE-fed sows had a greater ADG in parity 2 but lower ADG in parity 3 vs. litters from CON-fed sows (0.99 vs. 0.94 and 0.93 vs. 1.01 ± 0.03 kg/d for parities 2 and 3, respectively; P < 0.05). No differences were observed for ADG or ADFI in the finisher phase or G:F in any phase for any parity. Loin eye area was smaller (52.2 vs. 55.0 ± 1.8 cm2; P < 0.05) for offspring from PRE- vs. CON-fed sows. In parity 2, carcass lean yield tended to be less for offspring from PRE- vs. CON-fed sows (58.6 vs. 59.6 ± 0.4%; P = 0.051). Minimal differences were observed for subjective and objective evaluations of loin quality. Closely meeting the estimated daily energy and Lys requirements for sows throughout gestation for three consecutive pregnancy cycles improved offspring growth performance (ADG and ADFI) in the final nursery stage, but generally did not affect growth performance in grower/finisher periods or carcass and loin quality at ~125 kg BW.

Starvation and Its Effects on the Gut

There is growing awareness that intestinal dysfunction determines the clinical outcomes of situations as diverse as undernourished children in urban tropical slums and undernourished surgical patients in intensive care units. As experimental starvation in humans has only rarely been studied, and largely not using current biomedical research tools, we must draw inference from disparate clinical and experimental observations as to the derangements present in the starved gut. There is good evidence of intestinal atrophy and achlorhydria in starvation and severe undernutrition. Historical reports from concentration camps and conflict settings consistently reported a noncontagious phenomenon called "hunger diarrhea," but in settings where starved individuals are isolated from others (prisoners on hunger strike, anorexia nervosa) diarrhea is not a feature. Changes in intestinal permeability and absorption have been infrequently studied in experimental starvation; available data suggest that short-term starvation reduces sugar absorption but not permeability. Severe acute malnutrition in children is associated with severe changes in the intestinal mucosa. Experimental animal models may help explain some observations in humans. Starved rats develop a hypersecretory state and intestinal barrier defects. Starved pigs demonstrate prolongation of rotavirus diarrhea and reproduce some of the absorptive and barrier defects observed in malnourished children. However, there remains much to be learned about the effects of starvation on the gut. Given the high prevalence of undernutrition in hospitals and disadvantaged communities, the lack of attention to the interaction between undernutrition and gastrointestinal damage is surprising and needs to be corrected. Current sophisticated cellular and molecular techniques now provide the opportunity to create fresh understanding of gastrointestinal changes in pure undernutrition, using volunteer studies and samples from anorexia nervosa.

The Melatonin and Enriched Environment Ameliorated Low Protein-Induced Intrauterine Growth Retardation by IGF-1 And mtor Signaling Pathway and Autophagy Inhibition in Rats

CDATA[Aim: The present study investigated whether melatonin (MEL) and enriched environment (EE) might protect against intrauterine growth retardation (IUGR) in rats.

METHODS

Sprague-Dawley rats were randomly allocated to 3 groups: control (C), model (M) and EE+MEL group. Animals were housed in an enriched environment (EE+MEL group) or remained in a standard environment (C group, M group). IUGR rat model was built by feeding a low protein diet during pregnancy. MEL was administered by gavaging. At day 1 post-birth, the baseline characteristics and serum biochemical parameters, morphology of liver and small intestine, enzyme activities, and mRNA expression levels of fetal rats were determined. The autophagy marker LC3 and Beclin1 were determined by western blot analysis.

RESULTS

EE+MEL markedly improved the baseline characteristics, hepatic and intestinal morphology of IUGR fetuses. In addition, the lactase activities in the fetal intestine were markedly increased by the EE+MEL. The levels of serum somatostatin (SST), Growth hormone (GH), GH releasing hormone (GHRH), Insulin-like Growth Factor 1 (IGF-1), triiodothyronine (T3), and tetraiodothyronine (T4) were found to be recovered by EE+MEL. In addition, the EE+MEL significantly ameliorated the mRNA expression of SST, GHRH, and GHRH receptor (GHRHR), GH, GHR, IGF-1, and IGF-1 receptor (IGF1R), IGF binding protein-1 (IGFBP1), mammalian target of rapamycin (mTOR), S6 kinase 1 (S6K1) and eukaryotic initiation factor 4E (eIF4E)-binding protein 1 (4EBP1) in fetuses. In IUGR fetal livers, LC3 and Beclin1 were found to be increased at birth, while LC3 and Beclin1 were observed to be significantly decreased in the EE+MEL group.

CONCLUSION

EE+MEL could improve fetal rats' baseline characteristics, serum biochemical parameters, birth weight, intestinal and hepatic morphology and enzyme activities. These effects could be explained by the activation of the IGF-1/IGFBP1 and IGF-1/mTOR/S6K1/4EBP1 signaling pathway and autophagy inhibition.

Maternal organic selenium supplementation during gestation improves the antioxidant capacity and reduces the inflammation level in the intestine of offspring through the NF-κB and ERK/Beclin-1 pathways

Selenium (Se) is postulated to protect against inflammation in the gut by attenuating oxidative stress. This study was conducted to investigate the effects of maternal 2-hydroxy-4-methylselenobutanoic acid (HMSeBA), an organic Se source, on the intestinal antioxidant capacity and inflammation level of the offspring and its possible mechanism. Forty-three sows were randomly assigned to receive one of the following three diets during gestation: control diet, sodium selenite (Na₂SeO₃) supplemented diet or HMSeBA supplemented diet, respectively. Samples were collected from the offspring at birth and weaning. The results showed that maternal HMSeBA supplementation significantly upregulated ileal GPX2 and SePP1 gene expression compared with the control and Na₂SeO₃ groups, while suppressed the expression of ileal IL-1β, IL-6 and NF-κB genes in newborn piglets compared with the control group. Moreover, maternal HMSeBA supplementation significantly increased the protein of ileal GPX2 and p-mTOR compared with the control and Na₂SeO₃ groups, but decreased the ileal p-NF-κB, Beclin-1 and p-ERK proteins in newborn piglets compared with the control group. The weaned piglets of the HMSeBA group had lower serum IL-1β and IL-6 than the piglets of the control group at 2 h of LPS challenge. In addition, after the LPS challenge, the HMSeBA group had a lower relative abundance of ileal p-NF-κB and Beclin-1 proteins than the control and Na₂SeO₃ groups. In conclusion, maternal HMSeBA supplementation during gestation can improve the offspring's intestinal antioxidant capacity and reduce the inflammation level by suppressing NF-κB and ERK/Beclin-1 signaling.

Effects of a Diet Supplemented with Exogenous Catalase from Penicillium notatum on Intestinal Development and Microbiota in Weaned Piglets

This study aims to investigate the effects of exogenous catalase (CAT), an antioxidative enzyme from microbial cultures, on intestinal development and microbiota in weaned piglets. Seventy-two weaned piglets were allotted to two groups and fed a basal diet or a basal diet containing 2.0 g/kg exogenous CAT. Results showed that exogenous CAT increased (p < 0.05) jejunal villus height/crypt depth ratio and intestinal factors (diamine oxidase and transforming growth factor-α) concentration. Moreover, dietary CAT supplementation enhanced the antioxidative capacity, and decreased the concentration of pro-inflammatory cytokine in the jejunum mucosa. Exogenous CAT did not affect the concentration of short-chain fatty acids, but decreased the pH value in colonic digesta (p < 0.05). Interestingly, the relative abundance of Bifidobacterium and Dialister were increased (p < 0.05), while Streptococcus and Escherichia-Shigella were decreased (p < 0.05) in colonic digesta by exogenous CAT. Accordingly, decreased (p < 0.05) predicted functions related to aerobic respiration were observed in the piglets fed the CAT diet. Our study suggests a synergic response of intestinal development and microbiota to the exogenous CAT, and provides support for the application of CAT purified from microbial cultures in the feed industry.

Responses of intestinal morphology and function in offspring to heat stress in primiparous sows during late gestation

Late gestation is a key period for intestinal development. Maternal heat exposure may induce intestinal dysfunction of offspring. To investigate the responses of intestinal morphology and function of offspring to the maternal heat stress (HS), twelve first-parity Landrace × Large White sows were assigned to thermoneutral (TN) (18-22 °C; n = 6) or HS (28-32 °C; n = 6) treatment groups at 85 d of gestation until natural farrowing. Twenty-four newborn piglets (two piglets at medium body weight from each litter) were randomly selected and divided into in utero thermoneutral (IUTN, n = 12) and heat-stressed (IUHS, n = 12) groups according to the sow's treatment. Blood and intestinal samples were harvested to evaluate stress hormone levels, intestinal morphology, integrity and barrier function in the newborn piglets. Our results showed that maternal HS piglets exhibited increased serum adrenocorticotropic hormone (ACTH) concentration compared with that observed in the IUTN group. IUHS piglets showed lower lactase activities in the jejunum and ileum, whereas no significant differences were found between the two groups in the length of intestine, villus length or crypt depth. Serum diamine oxidase (DAO) activity was increased in IUHS piglets. IUHS piglets also exhibited decreased ZO-1, ZO-2 and MUC2 mRNA expression in the jejunum, while the protein levels were not affected. Additionally, IUHS piglets had a lower apoptotic percentage and FAS mRNA expression in the jejunum than those in the IUTN group. Taken together, these results demonstrate that high ambient temperature during late gestation of primiparous sows causes stress response in neonatal piglets, compromising intestinal permeability and mucosal barrier function, which may be partly mediated by inducing intestinal apoptosis.

Effects of the Ratio of Insoluble Fiber to Soluble Fiber in Gestation Diets on Sow Performance and Offspring Intestinal Development

Simple Summary

Gestating sows fed a diet rich in dietary fiber show improved performance. Dietary fiber is composed of insoluble fiber and soluble fiber. The ratio of insoluble to soluble fiber may affect overall diet utilization and influence sow performance. Maternal nutrition significantly affects offspring intestinal development; therefore, we investigated the effects of the ratio of insoluble to soluble fiber in gestation diets on sow performance and offspring intestinal development. Our results suggested that, when the dietary fiber levels were the same in gestation diets, the ratio of insoluble to soluble fiber affected the development of intestinal morphology and enzymatic activity related to nutrient digestion and absorption, and consequently affected the average daily gain during lactation and average piglet body weight at weaning. When the ratio of insoluble to soluble fiber was 3.89 in the gestation diet, higher average piglet body weight and litter weight at weaning were observed. These results may provide guidance for the application of fiber in pig production.

Abstract

To investigate the effects of the ratio of insoluble fiber to soluble fiber (ISF:SF) on sow performance and piglet intestinal development, we randomly assigned 64 gilts to four treatments comprising diets with the same level of dietary fiber, but different ISF:SF values of 3.89 (T1), 5.59 (T2), 9.12 (T3), and 12.81 (T4). At birth and weaning, six piglets per treatment at each phase were slaughtered for sampling. As ISF:SF increased, the mean piglet body weight (BW) at weaning and piglet BW gain, which were all significantly higher in T1 and T2 compared with T3 and T4 (p < 0.05), showed a linear decrease (p < 0.05); the crypt depth of the jejunum in weaned piglets linearly increased, whereas the duodenal weight, jejunal villus height, and villus height/crypt depth in newborn piglets and enzymatic activity of lactase, sucrase, and maltase linearly decreased (p < 0.05). No differences were observed in the yield and composition of milk (p > 0.05). Moreover, when the ISF:SF was 3.89 in gestation diets, higher piglet BW at weaning occurred, possibly because the ISF:SF affected development and enzymatic activity in the small intestine—effects related to digestion and absorption of nutrients—and consequently enhanced piglet BW gain.

Protein Malnutrition During Juvenile Age Increases Ileal and Colonic Permeability in Rats

Protein malnutrition can lead to morphological and functional changes in jejunum and ileum, affecting permeability to luminal contents. Regarding the large intestine, data are scarce, especially at juvenile age. We investigated whether low-protein (LP) diet could modify ileal and colonic permeability and epithelial morphology in young rats. Isocaloric diets containing 26% (control diet) or 4% protein were given to male rats between postnatal days 40 and 60. LP-diet animals failed to gain weight and displayed decreased plasma zinc levels (a marker of micronutrient deficiency). In addition, transepithelial electrical resistance and occludin expression were reduced in their ileum and colon, indicating increased gut permeability. Macromolecule transit was not modified. Finally, LP diet induced shortening of colonic crypts without affecting muscle thickness. These data show that protein malnutrition increases not only ileum but also colon permeability in juvenile rats. Enhanced exposure to colonic luminal entities may be an additional component in the pathophysiology of protein malnutrition.

Dietary supplementation with tributyrin prevented weaned pigs from growth retardation and lethal infection via modulation of inflammatory cytokines production, ileal expression, and intestinal acetate fermentation

Weanling pigs, with an underdeveloped intestine and immature immune system, are usually subjected to depressed feed intake, growth retardation, and postweaning diarrhea. The aim of this study was to determine 1) the growth response of weaned pigs to supplemental tributyrin (TB) and 2) the potential effects and mechanisms of TB in modulating immune responses of lipopolysaccharide (LPS)-challenged piglets. A total of 240 piglets (Duroc × Large White × Landrace) were weaned at 21 d of age to a control (basal diet), supplemented with antibiotics (AB; +AB), supplemented with TB (+TB), or with supplemental AB and TB (+AB+TB) diets, with 10 replicate pens (6 piglets/pen) per diet. At 49 d of age, male pigs from the control and +TB groups were intraperitoneally injected with LPS (25 μg/kg BW) or saline ( = 6) and sacrificed at 4 h after injection to collect blood, intestine, and digesta samples for biochemical analysis. There were higher ( < 0.05) feed intake and lower ( < 0.05) percentage of negative growth piglets in the +TB groups than in the control group during the first week after weaning. For piglets without LPS challenge, there were higher ( < 0.05) ileal fibroblast growth factor 19 () mRNA abundance and total bile acid concentrations in the +TB groups than in the control group, whereas downregulated ( < 0.05) expression was observed in the +TB groups after LPS challenge. Lipopolysaccharide challenge in the control group increased ( < 0.05) plasma tumor necrosis factor α and IL-6 concentrations and colonic amount and decreased ( < 0.05) colonic goblet cells and colonic and cecal acetate concentrations, with no differences ( > 0.05) observed between +TB groups following LPS challenge. Taken together, dietary supplementation with TB prevented growth retardation through stimulating the appetite of weaned pigs and protected piglets against lethal infection via modulation of inflammatory cytokines production, ileal expression, and intestinal acetate fermentation.

Di- and tripeptide transport in vertebrates: the contribution of teleost fish models

Solute Carrier 15 (SLC15) family, alias H⁺-coupled oligopeptide cotransporter family, is a group of membrane transporters known for their role in the cellular uptake of di- and tripeptides (di/tripeptides) and peptide-like molecules. Of its members, SLC15A1 (PEPT1) chiefly mediates intestinal absorption of luminal di/tripeptides from dietary protein digestion, while SLC15A2 (PEPT2) mainly allows renal tubular reabsorption of di/tripeptides from ultrafiltration, SLC15A3 (PHT2) and SLC15A4 (PHT1) possibly interact with di/tripeptides and histidine in certain immune cells, and SLC15A5 has unknown function. Our understanding of this family in vertebrates has steadily increased, also due to the surge of genomic-to-functional information from 'non-conventional' animal models, livestock, poultry, and aquaculture fish species. Here, we review the literature on the SLC15 transporters in teleost fish with emphasis on SLC15A1 (PEPT1), one of the solute carriers better studied amongst teleost fish because of its relevance in animal nutrition. We report on the operativity of the transporter, the molecular diversity, and multiplicity of structural-functional solutions of the teleost fish orthologs with respect to higher vertebrates, its relevance at the intersection of the alimentary and osmoregulative functions of the gut, its response under various physiological states and dietary solicitations, and its possible involvement in examples of total body plasticity, such as growth and compensatory growth. By a comparative approach, we also review the few studies in teleost fish on SLC15A2 (PEPT2), SLC15A4 (PHT1), and SLC15A3 (PHT2). By representing the contribution of teleost fish to the knowledge of the physiology of di/tripeptide transport and transporters, we aim to fill the gap between higher and lower vertebrates.

Impact of acute undernutrition on growth, ileal morphology and nutrient transport in a murine model

Undernutrition represents a major public health challenge for middle- and low-income countries. This study aimed to evaluate whether a multideficient Northeast Brazil regional basic diet (RBD) induces acute morphological and functional changes in the ileum of mice. Swiss mice (∼25 g) were allocated into two groups: i) control mice were fed a standard diet and II) undernourished mice were fed the RBD. After 7 days, mice were killed and the ileum collected for evaluation of electrophysiological parameters (Ussing chambers), transcription (RT-qPCR) and protein expression (western blotting) of intestinal transporters and tight junctions. Body weight gain was significantly decreased in the undernourished group, which also showed decreased crypt depth but no alterations in villus height. Electrophysiology measurements showed a reduced basal short circuit current (I_sc) in the undernourished group, with no differences in transepithelial resistance. Specific substrate-evoked I_sc related to affinity and efficacy (glutamine and alanyl-glutamine) were not different between groups, except for the maximum I_sc (efficacy) induced by glucose. Transcription of Sglt1 and Pept1 was significantly higher in the undernourished group, while SN-2 transcription was decreased. No changes were found in transcription of CAT-1 and CFTR, while claudin-2 and occludin transcriptions were significantly increased in the undernourished group. Despite mRNA changes, SGLT-1, PEPT-1, claudin-2 and occludin protein expression showed no difference between groups. These results demonstrate early effects of the RBD on mice, which include reduced body weight and crypt depth in the absence of significant alterations to villus morphology, intestinal transporters and tight junction expression.

Maternal high fat intake affects the development and transcriptional profile of fetal intestine in late gestation using pig model

Background

The objective of this study was to investigate the effects of maternal high fat intake on intestinal development and transcriptional profile.

Methods

Eight gilts with similar age and body weight were randomly allocated into 2 groups receiving the control and high fat diets (HF diet) from d 30 to 90 of gestation, with 4 gilts each group and one gilt each pen. At d 90 of gestation, two fetuses each gilt were removed by cesarean section. Intestinal samples were collected for analysis of morphology, enzyme activities and transcriptional profile.

Results

The results showed that feeding HF diet markedly increased the fetal weight and lactase activity, also tended to increase intestinal morphology. Porcine Oligo Microarray analysis indicated that feeding HF diet inhibited 64 % of genes (39 genes down-regulated while 22 genes up-regulated),which were related to immune response, cancer and metabolism, also markedly modified 33 signal pathways such as antigen processing and presentation, intestinal immune network for IgA production, Jak-STAT and TGF-ß signaling transductions, pathways in colorectal cancer and glycerolipid metabolism.

Conclusion

Collectively, it could be concluded that maternal high fat intake was able to increase fetal weight and lactase activity, however, it altered the intestinal immune response, signal transduction and metabolism.

Electronic supplementary material

The online version of this article (doi:10.1186/s12944-016-0261-0) contains supplementary material, which is available to authorized users.

A Maternal High-Energy Diet Promotes Intestinal Development and Intrauterine Growth of Offspring

It has been suggested that maternal nutrition during gestation is involved in an offspring’s intestinal development. The aim of this study was therefore to evaluate the effects of maternal energy on the growth and small intestine development of offspring. After mating, twenty gilts (Large White (LW) breeding, body weight (BW) at 135.54 ± 0.66 kg) were randomly allocated to two dietary treatments: a control diet (CON) group and a high-energy diet (HED) group, respectively. The nutrient levels of the CON were referred to meet the nutrient recommendations by the National Research Council (NRC, 2012), while the HED was designed by adding an amount of soybean oil that was 4.6% of the total diet weight to the CON. The dietary treatments were introduced from day 1 of gestation to farrowing. At day 90 of gestation, day 1 post-birth, and day 28 post-birth, the weights of fetuses and piglets, intestinal morphology, enzyme activities, and gene and protein expressions of intestinal growth factors were determined. The results indicated that the maternal HED markedly increased the BW, small intestinal weight, and villus height of fetuses and piglets. Moreover, the activities of lactase in fetal intestine, sucrase in piglet intestine were markedly increased by the maternal HED. In addition, the maternal HED tended to increase the protein expression of insulin-like growth factor 1 receptor (IGF-1R) in fetal intestine, associated with significantly increased the gene expression of IGF-1R. In conclusion, increasing energy intake could promote fetal growth and birth weight, with greater intestinal morphology and enzyme activities.

Influence of Butyrate Loaded Clinoptilolite Dietary Supplementation on Growth Performance, Development of Intestine and Antioxidant Capacity in Broiler Chickens

The study was conducted to evaluate the effects of dietary butyrate loaded clinoptilolite (CLI-B) on growth performance, pancreatic digestive enzymes, intestinal development and histomorphology, as well as antioxidant capacity of serum and intestinal mucosal in chickens. Two hundred forty 1-day-old commercial Arbor Acres broilers were randomly assigned to 4 groups: CON group (fed basal diets), SB group (fed basal diet with 0.05% sodium butyrate), CLI group (fed basal diet with 1% clinoptilolite), and CLI-B group (fed basal diet with 1% CLI-B). The results showed that supplementation of CLI-B significantly decreased (P < 0.05) feed conservation ratio at both 21 and 42 days of age, improved the pancreatic digestive enzymes activities (P < 0.05), increased the villus length and villus/crypt ratio (P < 0.05), and decreased the crypt depth of intestine (P < 0.05) as compared to the other experimental groups. Furthermore, the CLI-B environment improved the antioxidant capacity by increasing the antioxidant enzyme activities (P < 0.05) in intestine mucosal, and decreasing the NO content and iNOS activity (P < 0.05) in serum. In addition, CLI-B supplementation had improved the development of intestine and antioxidant capacity of broilers than supplementation with either clinoptilolite or butyrate sodium alone. In conclusion, 1% CLI-B supplementation improved the health status, intestine development and antioxidant capacity in broiler chickens, thus appearing as an important feed additive for the poultry industry.

Human Intestinal PEPT1 Transporter Expression and Localization in Preterm and Term Infants

The intestinal influx oligopeptide transporter peptide transporter 1 (PEPT1) (SLC15A1) is best known for nutrient-derived di- and tripeptide transport. Its role in drug absorption is increasingly recognized. To better understand the disposition of PEPT1 substrate drugs in young infants, we studied intestinal PEPT1 mRNA expression and tissue localization across the pediatric age range. PEPT1 mRNA expression was determined using real-time reverse-transcription polymerase chain reaction in small intestinal tissues collected from surgical procedures (neonates and infants) or biopsies (older children and adolescents). PEPT1 mRNA relative to villin mRNA expression was compared between neonates/infants and older children/adolescents. PEPT1 was visualized in infant tissue using immunohistochemical staining. Other transporters [multidrug resistance protein 1 (MDR1), multidrug resistance-like protein 2 (MRP2), and organic anion transporter polypeptide 2B1 (OATP2B1)] were also stained to describe the localization in relation to PEPT1. Twenty-six intestinal samples (n = 20 neonates/infants, n = 2 pediatric, n = 4 adolescents) were analyzed. The young infant samples were collected at a median (range) gestational age at birth of 29.2 weeks (24.7-40) and postnatal age of 2.4 weeks (0-16.6). The PEPT1 mRNA expression of the neonates/infants was only marginally lower (0.8-fold) than the older children (P < 0.05). Similar and clear apical PEPT1 and MRP2 staining, apical and lateral MDR1 staining, and intraepithelial OATP2B1 staining at the basolateral membrane of the enterocyte were detected in 12 infant and 2 adolescent samples. Although small intestinal PEPT1 expression tended to be lower in neonates than in older children, this difference is small and tissue distribution is similar. This finding suggests similar oral absorption of PEPT1 substrates across the pediatric age range.

Effects of dietary lysozyme levels on growth performance, intestinal morphology, non-specific immunity and mRNA expression in weanling piglets

The aim of the present study was to determine the effect of dietary lysozyme levels on growth performance, gut health and non-specific immunity of weanling piglets. A total of 150 weanling piglets were allocated to six treatments. The piglets were fed the same basel diet supplemented with 0, 30, 60, 90 and 120 mg/kg lysozyme as well as antibiotics for 28 days. From day 14 to day 28 of dietary treatment, piglets fed 90 mg/kg lysozyme had greater average daily gain than piglets fed control diet. During the whole experimental period, piglets fed 120 mg/kg lysozyme tended to have greater average daily gain than piglets fed control diet. Compared with piglets fed control diet, piglets fed diets containing antibiotics and 90 mg/kg lysozyme had greater villus height to crypt depth ratio in duodenum and jejunum. Additionally, dietary supplementation of 60 and 90 mg/kg lysozyme as well as antibiotics enhanced the phagocytic activity of peritoneal macrophages in piglets. In conclusion, dietary lysozyme can accelerate the growth of weanling piglets by improving gut health and non-specific immunity and supplementing 90 mg/kg lysozyme is as effective as antibiotics (20 mg/kg colistin sulphate + 50 mg/kg kitasamycin) in improving the growth performance of weanling piglets.

Oral administration of Lactococcus lactis-expressed recombinant porcine epidermal growth factor stimulates the development and promotes the health of small intestines in early-weaned piglets

AIMS

We previously generated Lactococcus lactis-expressed recombinant porcine epidermal growth factor (LL-pEGF), and demonstrated improved growth performance in early-weaned piglets. This study investigates the effect of LL-pEGF on the development and expression of genes that maintain the structural integrity and function of the small intestine in early-weaned piglets.

METHODS AND RESULTS

The mitogenic effect of porcine epidermal growth factor (pEGF) was tested in vitro with the 5-Bromodeoxyuridine (BrdU) incorporation assay in fibroblast cells. In the in vivo study, 40 weaned piglets were randomly allocated to control, antibiotic control, Lc. lactis-expressing empty vector (LL-EV) and LL-pEGF treatment groups. Cells treated with LL-pEGF had higher BrdU-positive stained cells than those in the control and the LL-EV treatments (P < 0·05). Scanning electron microscope and histological examination demonstrated that the small intestinal villi treated with LL-pEGF were higher (P < 0·05) than in the other treatments. LL-pEGF increased the messenger RNA (mRNA) expression levels of the intestinal structural integrity proteins trefoil factor 3, claudin 1 (CLDN1), occludin and zonula occludens 1 (ZO-1), the digestive enzymes sucrose, aminopeptidase A, and aminopeptidase N, and the nutrient transporters sodium/glucose cotransporter 1 (SGLT1), glucose transporter 2, and peptide transporter 1 (PEPT1) as compared with the control (P < 0·05) in the small intestine. Meanwhile, the mRNA levels of CLDN1 in the jejunum and ZO-1 in the ileum were higher in the LL-EV group than in the control group (P < 0·05). LL-EV and the antibiotic control increased SGLT1 mRNA in the jejunum and PEPT1 mRNA in the ileum compared with the control (P < 0·05).

CONCLUSIONS

Recombinant pEGF promotes cell mitosis. Oral administration of Lc. lactis-expressing pEGF stimulated intestinal development by upregulating the gene expression of the intestinal structural integrity proteins, the digestive enzymes and the nutrient transporters.

SIGNIFICANCE AND IMPACT OF THE STUDY

The combination of epidermal growth factor and genetically modified micro-organisms may be used as dietary supplements to reduce intestinal stress in animals and even humans.